Fuel injection means for compressorless internal combustion engines



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FUEL I'NJECTION MEA S FOR COMPRESSORLESS INTERNAL COMBUSTIONENGINES IFiled Jan. 8,1935

a means according to the invention.

In the embodiment of invention shown,,the high uurnznjsmr Patented Oct.1, u

- FUEL INJECTION it *SORLESSQ, INTERNAL COMBUSTION En GINES Th orleifEek, Oslo, No'rway, assignor to Koch urns Mekaniska Verkstads Sweden, acorporation of Sweden" Aktiebolag, j Mal no, 1

ApplicationJanuary s, 1935, Serial No. 907

p In Sweden November 13, 1934 r i 3 Claims. (Cl. 299-1072) V The presentinvention refers to fuel injection means for internal combustion engineshaving no fuel compressor. More specifically the invention refers tosuch compressorless internal combustion engines in which the high fuelpressure required for the injection is brought about by means of apiston pump driven by a compressed fluid, jand whereinthe injection isperformed by means of a nozzle controlled by aneedle valve,

In injection means of this kind, the invention hasfor its primary objecttoimprove the working conditions of the high pressure fuel pump so as toobtainan efficient fuel injections,

Generally speaking, the main characteristic of the invention is that thefuel conveying conduit between the high pressure pump and theneedlevalve, or nozzle, is providedwith a shut-off valve means adapted tocoact with thefmovable members of the high pressure piston pump in,sucha manner that the said conveying conduit is closed at the conclusionof the injection stroke of r the D p s i j i The result hereof will bethat the fuel confined betweenthe fuel piston of the high pressure thatthe piston will be permitted to continue its injection stroke until thecompression of the conflnedfuel is sufiicient for eifecting aicompletestopping of the same, and in that the piston, after having been reversedat the, end of the injection stroke, may perform a certain part of itssuction 1 stroke before the valve. member is opened again,

so that the pressure of the confined quantity of fuel has got time todecrease sufiiciently for eliminating the risk of after-injection offuel into the engine cylinder.

An embodiment of the invention illustrated in the accompanyingdiagrammatical drawing which shows a longitudinal section of the upperportion of an engine cylinder equipped with the injection pressurepiston pump is supposed to be provided with a differential piston .lthelarger piston member ofwhich is adapted to be driven by a comdecreasein 'a'sufiicient degree for eliminating an after-injection.

pressed fluid, whereas the smaller plunger member of the'same is adaptedto exert the required pressure on the fuel, such differential pistonbeing reciprocably mounted within a housing 3 enclos-. ing alsotheneedle valve 2. r i

The highly compressed fuel is injected through the engine after havingat first passed a communication conduit 1 connecting the needle valveand'the nozzle with the fuel compression cylinder 8 of, the highpressure pump.

The shut-off valve member 6 is connected with the free end of the highpressure plunger by means of a coil spring 9, and said valve member isadapted to coact with a seat In provided at the 1 bottom end of thecylinder 8 and forming the inlet opening to the communication conduit 1.Y

i The fuel enters the cylinder Bbymeans of an admission channel I I, andthe driving fluid for l3 by means of the pipe l2. When the differentialpiston l is moved downwardly under influence from the pressure withinthe cylinder l3, the fuel is compressed within the cylinder 8 andinjected into the engine cylinder by the intermediary of the.communication conduit l, theneedle valve 2 and the nozzle 4. At theconclusion of the injection stroke of the pump, the valve member 6approaches the seat In and is pressed, against the .sameundercompression of 39 i r the spring 9, so thatthe inlet end of theconduit I becomes closed. The fuel confined between the lower end faceof the fuel piston and the valve member 6 is thereafter compressed andarrests PATENT ornatthe nozzle 4 into the, combustion chamber 5 of thehigh pressure pump is admitted to the cylinder 20 the movement of thepiston. The valve member 5 will be kept againstits seatalso during thefirst part of the suctionstroke of the piston, and until the pressurewithin thecylinder 8 has got time to' WhatI claim and desire to secureby Letters Patent is:- i V 1. In a fuel injection means for internalcombustion engines of the character described, a high pressure pistonpump driven by a compressed 5 fluid and adapted to raise thepressure-onthe fuel in a. sufficient degree for injection into the working cylinderof the engine, an injection nozzle means mounted in connection with theengine cylinder and adapted for injection of the fuel therein, e valvemeans adapted for closing of said nozzle means, a communication conduitbetween said nozzle means and the high pressure fuel chamber of thepiston pump, and a shut-offvalve means resiliently connected with thepiston of the high pressure fuel pump and adapted for closing of theaforesaid communication conduit at the conclusion of the injectionstroke of said pump.

2. In a fuel injection means for internal combustion engines of thecharacter described, a high pressure fuel piston pump having adifierential piston the larger piston member of which is adapted to bedriven by a compressed fluid, whereas the smaller piston member of thesame is adapted to exert the required pressure on the fuel, an injectionnozzle means mounted in connection with the engine cylinder and adaptedfor injection of the fuel therein, a valve means adapted for closing ofsaid nozzle means, a communication conduit between said nozzle means andthe high pressure fuel chamber of the piston pump, and a shut-off valvemeans resiliently connected with the smaller piston member of thedifferential piston and adapted for closing of the said communicationconduit at the conclusion of the injection stroke of the pump.

3. In a fuel injection means according to claim 2, the additionalfeature, that the shut-01f valve means for the communication conduit ismounted at the free end of the smaller piston member of 10 thedifferential piston and adapted to coact with a seat at the bottom ofthe cylinder within which said piston member moves, such seat formingthe inlet end of said communication conduit.

THORLEIF EEK.

